Is there a low cost way to repeat a 2.4Ghz signal?

I own a small gym where I have installed a heart rate monitoring system. Participants wear a belt around their chest that transmits their heart rate to an antenna that is hooked up to a computer. According to the manufacturer, the belts transmit at 2.45GHz (between WLAN channels 11 and 12) . There are certain points in my facility that the signal drops off from the system. I believe this is because there are too many walls in the way.
Is there a device available that would pick up the 2.45GHz signal from multiple heart rate monitors and repeat it or amplify it so that it can reach the system’s antenna?